Detector



Patented June 3, 1924.,

ITD ST TES lftddi PATENT FFHC..

DETECTOR.

Application filed February 24s, 19273. Serial No. @21,049.

To all whom t may concer/lt.'

Be it known that I, HUGO GERNsBAcK, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in a Detector, ofwhich the following is a specification.

This invention relates to radio apparatus and more particularly todetectors of the crystal type and the primary object of the invention isto provide an improved detector, which will operate efficiently underall conditions and in which a lgood contact between ythe feeler7 and.the crystal .is estalr lished at all times.

Iii crystal detectors ofthe ordinary type,

a `feeler wire or a cat-whisker,7 as thesame is commonly called, isutilized Yfor finding and establishing contact with a sensitive point onthe crystal. rl`he single feeler wire or cat-Whisker is Ausually knockedout of contact by the impact or vibration andy it then becomes necessaryto hunt all over the surface of the crystal again to tind a newsensitive point. e

It is therefore Yanother rprime object of the invention, to provide adetector in which the above mentioned diiiiculty is eliminated and inwhich the single feeling wire or"cat Whisker is disposed with and afeelermember substituted therefor having a plural-ity of feeling orcontact points for engaging a plurality of different places on thecrystal, so that if one point is displaced from out of engagement with asensitive .spot von the crystal, other feeler points will automaticallyengage other sensitive spots on the cry-stal, whereby a crystal detector-is provided which works permanently, as has been actually found to bethe case in practice.

A further object of the inventionfisto provide an improved crystaldetector embodying the usual crystal, an annular com pression gasket,feeler plates disposed inthe compression gasket for engaging the crystaland means for adjusting the plates' in'relation to the crystal, untilthe proper pressure between the plates and crystal is established. Viththese and other .objects in view the invention consists in the novelconstruction, arrangement and formation of parts, as will be hereinaftermore specifically described, claimed and illustrated in the accompanyingdrawings, in which drawings:

Figure l is a.' side-elevation `of Y j the improved crystal detector.

Figure 2 is a transverse vertical section through the same taken on theline 2-2 of lFigure 1.

one of the feeler plates taken on the line 5-5 of Figure 3.

Figure 6 is an elevation of a modified form of feeler, which can be usedwith the improved detector.

Figure 7 is a section through the `same taken on the line 7-*7 of Figure6.

Referring to the drawings Yin detail, wherein similar referencecharacters .designate corresponding parts throughout the several viewsthe letter A general-ly indicates a crystal, detector constructed inaccordance Iwith my 'invention which includes a base plate 10 formed yofinsulating material. A pair of resilient electric conducting supportingarms 11 and -12 .are secured in any preferred way to the base plate 10andthese arms are electrical-ly connected in any manner, as is well.known inthe art, with binding posts 13 and .14. These .resilientelectric constructingsupporting arms 11 and 12 are held in spacedinsulated relation, by means of a'projection 15 disposed between saidarms, which is formed on the upper'surface of the base plate 10. Theupper terminals of the arms l1 and l2 are provided with `struclcinsockets 16, for a purpose, which will 'be `hereinafter more fullydescribed.

letachably supported'by the arms 11 and 12 isthe detecting portion 17 ofthe apparatus which consists of a housing l18 formed of electricinsulating material. This housing 18 embodies an annular side wall 19and a disk-shaped end wall A2O. The inner surface of the annular sidewall I'19 can be provided with screw-threads y21 for the reception oftheadjusting plug 22, which is also formed of electric insulating material.This adjusting rplug 22 .includes a flat diskshaped ywall y23 and an'annular Aflange y24 having screw threads on its outer surface forengaging the threads 21 `formed on the wall 19 of the housing 17. Inyorder to permit the ready adjustment of the plug ,22 its wall 23 can beprovided with openings 2-5 for the reception of a Spanner wrench or thelike.

The walls 20 and 23 are provided with axially aligned openings 26 forthe reception of the outwardly extending axially disposed lugs 27 formedon the contact plates 28 and 29. The contact plate 29 is preferablyformed relatively thicker than the contact plate 28, so that the platewill have suiiicient weight and thickness for the purpose intended. Thelugs 27 are adapted to extend outwardly of the walls 20 and 23 andengage in the sockets 16 formed in the resilient supporting arms 11 and12.

Arranged within the housing 17 is the crystal proper 30 which can befitted in a block of wood metal 31. |Ihis block 31 engages the plate 28.

An annular compression washer 32 formed of cork, rubber, felt, or thelike is placed in engagement with the inner face of the block 31 andengages the inner face of the plate Disposed within the annularcompression gasket 32 is the feeler portion 33 of the apparatus whichforms the most vital part of my invention. A

This feeler portion 33 can be formed in different ways providing aplurality ot spaced contact points is formed for engaging the crystal 30and the contact plate 29.

In Figure 4 I have disclosed a plurality of feeler plates 34, 35 and 36,and in\actual practice I have found that three feeler plates can be usedto the best of advantage, but it is to be understood that only one platecan be used if so desired. The plate 35. is disposed between the plates34 and 36 and is provided with opposite plane faces. The plates 34 and36 have struckont from the body thereof outwardly extending contactpoints 37 which are adapted to engage respectively the crystal 30 andthe `contact plate 29. rIhe plates 34, 35 and 36 are preferably formedfrom gold, as gold has been found to be the only metal that gives ahighsensitivity with crystal galena, iron py` rites orother sensitivecrystal.. Gold .is not oxidizable and does not give rise lo surfaceresistance at the points, which are sharp. 7While, it is not desired tolimit the making of the plates of gold, nevertheless, gold has beenfound to be the best material. The Weight of the metal is also importantin the adjustment of the device, which will be hereinafter described.

In Figures 6 and 7 is shown another type of feeler which can be used inlieu of feeler plates, and as shown this feeler comprises a wire 40spirally wound, which is equipped to provide a plurality of oppositelydirected points 41 and 42. It is obvious however, that the feelers canbe made in other ways and I do not wish to' limit myself to the exactconstruction of the feeler, as in all probability other types of feelerscan be used providing the same are provided with a plurality of contactpoints.

One of the important features of the invention is the adjustmentprovided between the contact plates 28 and 29, whereby the correctpressure between the crystal 30 and the plate 29 is obtained. It isabsolutely necessary in connection with the detector, that a pressurearrangement be provided.

In obtaining this pressure, the plug 22 is screwed in or out of thehousingl?. In actual practice the plug is screwed in up to a certaincritical point and once this critical pressure has been found, thedetector is sealed as at 45, by shellac, or other means.

This gives the detector a permanent setting.

It should be understood, that the plates 34, 35 and 36 are nevercompressed tightly, but they must always be slightly loose. Thereresults, thereby, a sort of microphonic contact which is very critical.If the pressure is not sufficient, the detector will not Work. In otherwords, if the plate or plates are too looseJ no results will beobtained. If too much pressure is applied, a permanent solid contact isestablished between the points and the crystal and the detector will notwork. It is this critical pressure that is very important.

It is obvious, that if the detector is jarred or vibrated in any way,and that one contact point which may have been in engage-r ment with asensitive point of the crystal becomes moved away from the same, thatone of the other points will lind another sen sitive point of thecrystal and thus a detector has been provided which in reality workspermanently.

Changes in details may be made without departing from the spirit or thescope of this invention. l,

`What I claim as new is 1. A detector comprising a pair of contactplates disposed in spaced relation, a crystal, an annular compressiblewasher surrounding the crystal and engaging one contact plate, a feelermember embodying a plurality of contact points disposed within thecompression washer for engaging the crystal and the mentioned contactplate and means for varying ythe pressure between the two pontactplates, as and for the purpose speci- 2. In a detector, a casing ofinsulation including an annular side wall provided with internal threadsand an end wall, a plug inserted into said housing including an outerwall and a threaded flange for engaging the threads of the side wall ofthe housing, the end wall of the housing and the wall of the plug havingaligned axial openings therein, contact plates disposed in the housinghaving outwardly extending contact lugs disposed in and projecting outof said openings, a crystal, a block for the crystal dislill) .lltl

posed in the housing engaging one contact plate, an annular compressiblewasher engaging the block and the other contact plate, a feeler memberdisposed within the coinpressible washer between the crystal and thelast mentioned contact plate, and a plurality of contact pointsfformedon the feeler member, the threaded plug forming means for adjusting thepressure on the compressible washer, whereby t-he position of the feelermember can be adjusted.

3. In a detector, a crystal, a block for the crystal, an annularcompressible washer engaging the block around the crystal, a pair ofcontact plates for engaging the block and the compressible washer, and afeeler member disposed within the compressible washer including aplurality of plates, certain of the plates having a plurality of contactpoints formed thereon.

4. In a detector, a crystal, a block supporting the crystal, an annularcompressible washer engaging one end of the block and surrounding thecrystal, a contact plate engaging the other end of the block, a secondcontact plate engaging the compressible washer, a feeler member disposedwithin the compressible washer between the last men` tioned contactplate and the crystal, said feeler member including a central platehaving plane faces and side plates having a plurality of contact feelerpoints formed thereon for engaging the crystal and the second mentionedplate, and means for adjusting the pressure between said contact plates.

5. In a crystal detector, a metal feeler plate having a plurality ofspaced feeler points struck-out from one face thereof.

6. In a crystal detector, a feeler member including a central platehaving plane opposite faces and side plates having a plurality ofvstruck-out feeler points thereon.

7. In a detector, a block of insulation, a pair of upstanding resilientelectric conducting arms secured to the block of insulation havingsockets formed therein adjacent to the outer ends thereof, a housingformed of insulating material including an annular side wall, an endwall, ai, plug of insulating material adjustably carried by the sidewall, the plug and end wall having aligned aXial openings, a crystaldisposed in the housing, a block for receiving the crystal, acompressible washer of annular configuration engaging the inner face o fthe block and surrounding the crystal, a contact plate engaging theouter face of the block, a second contact plate engaging the outer faceof the compressible Washer, outwardly extending contact lugs formed onthe Contact plates extending through said openings and de* tachablyfitted in said sockets, and a feeler member including a plurality ofcontact points disposed within the compressible washer and enga-ging thecrystal and they second mentioned contact plate.

In testimony whereof I aliixmy signature in presence of two witnesses.

HUG() GERNSBACK. Witnesses:

HALsEY M. KENNEDY, Jos. F. ODENBAOH.

